The present invention relates generally to telecommunications systems and, more particularly, concerns a global roaming service for telecommunications systems which permits extension of wireless services to a user anywhere including on-board an airplane.
Numerous schemes exist for permitting land-based mobile telephone roaming services. Today, through agreements between network operators, a user can place and receive telephone calls through their wireless telephone anywhere within the country and, in some cases, anywhere worldwide. When traveling from place to place on-board an aircraft, however, a wireless telephone user has very limited options for making or receiving telephone calls. For example, many airline operators prohibit the use of cellular telephones in-flight because of the perceived potential for interference with the aircraft's electronic systems. Moreover, there are technical difficulties in using a standard cellular telephone while in-flight. Specifically, the mobile unit could establish a line-of-sight to a large number of base stations simultaneously and cause problems with base station frequency re-use patterns. In addition, because many cellular base stations have antennas arranged for maximum gain in the horizontal direction, establishing significant signal strength from any base station while in-flight may be difficult despite a clear line-of-sight to several base stations.
Many airlines provide in-flight phone systems for their passengers. The existing in-flight phone systems, however, only have one-way or outgoing call capability. While passengers can place a call to any telephone number, calls cannot be automatically received during the flight. Thus, there remains a need for a telecommunications system which extends wireless services to users globally including while on-board an aircraft.